Retort system

ABSTRACT

A method for producing dental restoration components includes filling a retort cylinder of a retort system with a forming mass, the retort cylinder being at least partially encircled by a charging body, and hardening the forming mass. After the hardening of the forming mass, the retort cylinder and the charging body are removed from the forming mass, thereby leaving behind a retort. Thereafter, with the assistance of a press blank apparatus, a press blank having an outer contour substantially corresponding to the outer contour of the charging body is pressed into the retort.

TECHNICAL FIELD

[0001] The present invention relates to a method for producing dentalrestoration components, a retort system, and a press blank, allespecially for use in connection with dental ovens.

BACKGROUND OF THE INVENTION

[0002] Retort ovens have been known for a long time such as, forexample, as is disclosed in DE-OS 198 44 136. In retort ovens of thistype, a wax model of a dental restoration is embedded in a cast bed inorder to produce a negative form. The retort is then heated and warmedso that the model composed of wax melts and there remains thetemperature resistant negative form or mold in readiness for theintroduction thereinto of a to-be-pressed ceramic mass.

[0003] Dental restoration can demand decidedly different forms andvolumes. Correspondingly, at the same time several wax models arefrequently made ready in a single batch—that is, several wax models arepoured within a single retort—and, correspondingly, several ceramicrestoration pieces are produced via pressing. The pressing is performedwith ceramic mass which is introduced via a feed-in channel and formedinto the form mass by a press stamp during simultaneous heating of thenegative form.

[0004] The mass can be introduced in a pre-pressed condition, in apowder-type condition, or even in a fluid condition, whereby thepre-pressed form body is typically designated as a blank.

[0005] Instead of blanks, powder-formed ceramic masses can also bedeployed. The use of blanks has, on the one hand, the advantage that anexact or precisely measured amount of ceramic material is deployed sothat the operation of the stamp for exerting pressure in the press ovencan be exactly specified and can be corrected with a correspondingmaterial offset.

[0006] The dental restoration component to be produced can requiresignificantly different amounts of ceramic—either in the form of ceramicpowder or in the form of ceramic blanks.

[0007] In order to competently handle these requirements, the length ofthe ceramic blank can be adapted to the requirements, within certainlimits. The ceramic blank is introduced into the channel which remainsas the negative form of the retort cylinder. In order to achieve a pressresult of high quality, the ceramic blank must practically be comprisedof the same diameter as that of the retort cylinder.

[0008] One can, indeed, increase the length of the retort cylinder and,consequently, increase the possible length of the ceramic blank.However, in connection with an overly long length, there arises acomparatively large friction during the press process. This isunfavorable from, for example, the perspective of the adhesion/slidingfriction conditions during the press process, which have only beenstudied to a limited degree and in connection with which there occurpressure oscillations in the hollow space in which the dentalrestoration is configured.

[0009] In order to competently handle various sizes of dentalrestorations, it has heretofore typically been the practice to maintaina plurality of different retort cylinders in readiness so that, inconnection with larger dental restorations of large diameter, largerdiameter versions of the retort cylinder can be deployed.

[0010] However, maintaining in readiness an inventory of several retortsystems of various sizes is a relatively large effort, simply from thepoint of view of requiring a correspondingly large inventory.

[0011] In order to avoid this, it has frequently been the case that anaverage-sized configuration of a retort system or a retort arrangementis deployed and then several restoration components are stuck outwardlyfrom wax on the growth surface via corresponding support arms, so thatthe mass is, in total, somewhat enlarged and the blank can be betterexploited.

[0012] However, imperfect accommodation to the required dentalrestoration configurations leads to considerable material loss, since,in the case of an only partially pressed blank, the blank must, for allpractical purposes, be thrown away.

[0013] If, on the other hand, in connection with a desired largematerial mass, a blank of an overly long length is deployed such that itextends out of the channel of the corresponding retort cylinder, thedanger exists that the blank will tip, leading to an unstable pressprocess.

SUMMARY OF THE INVENTION

[0014] In contrast to the above-noted shortcomings, the presentinvention provides a solution to the challenge of providing a retortsystem, which is an improvement from the point of view of ease of manualmanipulation and cost.

[0015] In connection with the solution of the present invention, asingle retort system can by itself, surprisingly, handle a wider rangeof ceramic amounts, which are designated for dental restoration models.Via the inventive charging body, a markedly large dental restoration canbe created with the same retort system.

[0016] In this connection, a correspondingly thicker charging body,which, preferably, encircles the retort cylinder in an annular manner,is deployed. Due to the enlarged thickness, the thus-deployed ceramicblank can, at the same time, be longer without giving rise to a fearthat a downgrade in stability will occur.

[0017] To this extent, a mass increase to the third power can berealized via the diameter enlargement made possible by the invention sothat, as well, a significantly greater mass amount can be achieved witha comparatively thin charging body.

[0018] Preferably, the retort cylinder, and the charging body whichencircles it, have a round configuration. There then occurs, inconnection with the pressing of the ceramic blank, a centralized loadingimpact on the ceramic blank so that no tipping force is therebyintroduced on the blank.

[0019] In accordance with the present invention, the charging body canmelt, preferably together with the model mass. In this connection, thecharging body, as well as the model, can be comprised of wax and can bedisposed together with the melted wax of the model in the hollow spaceof the retort.

[0020] In accordance with the present invention, it is particularlyadvantageous if the charging body comprises a smooth outer surface. Dueto the smooth outer surface, it is ensured that an overly strongfriction between the hardened form mass and the ceramic blank does notoccur, thereby permitting the greatest possible disturbance-free slidefriction during the press process.

[0021] In accordance with the present invention, it is especiallyfavorable in this connection that the inner top surface of theretort—that is, the outer circumference of the press channel—typicallyhas small wax remnants still remaining thereon. Such wax remnantsoperate, surprisingly, as lubrication means without, however, formingdebris on the dental restoration.

[0022] In this connection, it is particularly advantageous that thegrowth channels, which correspond to the support arms in connection withthe wax model securement on the growth surfaces, are configuredcentrally—that is, clearly within the tube-shaped charging body, so thatthe outer regions of the ceramic blank do not project into the growthchannels or, at the least, do not project into the growth channels atthe end of the press process and, in any event, do not project so far asto reach the dental restoration.

[0023] It is to be understood that the lubrication effect of the waxremnants endures only so long as the temperature in the retort is not atleast substantially over the vaporization temperature of the modelmass—that is, this effect lasts during the preparation and pre-heatingof the retort oven for the respective actual press process.

[0024] In a further particularly favorable configuration, it is providedthat the charging body extends over the retort cylinder.

[0025] In this configuration, a somewhat longer blank can be deployed aswell without engendering any tipping danger.

[0026] In furtherance of this purpose, the charging body is disposed onthe retort cylinder before the growth on the growth base has begun.

[0027] It is to be understood that not only a tube-shaped charging bodyis contemplated in connection with the term “charging body”. Inaddition, for example, a charging body comprised of several ringsaxially and/or radially combined with one another can be deployed. It isto be understood that the radial diameter of the charging body can beadapted in any suitable desired manner to the requirements.

[0028] The deployment of the inventive charging body or bodies does notrule out the provision, in a conventional manner, of a growth surface,having a blind bore, which can serve as the growth base. If the chargingbody extends outwardly over this surface, the surface can, infurtherance of this purpose, comprise a corresponding through bore.

[0029] Any suitable desired coding system can be deployed todifferentiate the various charging bodies from one another. For example,different charging bodies can be differently colored.

[0030] If the outer form of the charging body deviates from an annularform, the possibility then also exists that the ceramic blank will befriction-free but, also, that the ceramic blank will be even moresecurely supported on its side. For example, a six-sided form can beselected in order to achieve the desired outer bracing.

[0031] Further advantages, features and details are set forth in thefollowing description of several embodiments of the present inventiontaken in connection with the figures of the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0032]FIG. 1 is a front elevational view, in partial section, of a firstembodiment of the inventive retort system;

[0033]FIG. 2 is a front elevational view, in partial section, of thecombination of a retort base and a retort cylinder for the embodimentshown in FIG. 1;

[0034]FIG. 3 is a front elevational view, in partial section, of amodified combination of a retort base and a retort cylinder for theembodiment shown in FIGS. 1 and 2;

[0035]FIG. 4 is a front elevational view, in partial section, of afurther modified combination of a retort base and a retort cylinder;

[0036]FIGS. 5, 6, 7, and 8 are plan views of respective variousembodiments of an inventive charging body; and

[0037]FIG. 9 is a front elevational view, in section, of a press formcreated in connection with the inventive method.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0038]FIG. 1 shows a first embodiment of the inventive retort system 10which comprises a retort base 12 from which a retort cylinder 14 extendsdownwardly, as viewed in the position shown in FIG. 1.

[0039] In accordance with the present invention, the side of the retortcylinder 14 is encircled by a charging body 16, whereby, in theillustrated embodiment shown in FIG. 1, the charging body 16 isannularly shaped and has a wall thickness of approximately one-half theradius of the retort cylinder.

[0040] The retort cylinder 14 comprises a growth surface 18 on its lowerregion on the end face thereof turned away from the retort base 12. Atleast one support arm comprised of wax is mounted on the growth surface18, whereby, in the illustrated embodiment, two support arms 20 and 22are configured. Wax models 24 and 26 are provided somewhat centrally inthe retort system 10 on the other ends of the support arms 20 and 22,the wax models corresponding in their form to the dental restorations.

[0041] In the operational condition shown in FIG. 1, the retort systemhas already been filled with a forming mass 28 which completely enclosesthe retort cylinder, the support arms, and the wax models without thepresence of any included air.

[0042] To effect the filling of the retort system 10, the retort systemcomprises a retort cover 30 which—as is also the case with the retortbase 12—is removable and is in the form of a cylindrical retort form 32,which can be, for example, comprised of a piece of a plastic pipe or canbe formed of cardboard. The orientation of the retort system 10 is, inthis connection, turned around so that the retort base 12 and the retortcylinder 14 assume the positions shown in FIG. 2. In this operationalcondition with the retort form 32 removed, the charging body 16 is,initially, inserted or twisted on.

[0043] The growth surface 18 comprises, in a conventional manner, ablind hole recess or receptacle 34 which is configured for the receiptof a growth plug or stopper in order that the support arm can beanchored in an improved manner to the growth surface 18. In theillustrated embodiment, the wax models 24 and 26 extend sufficientlyoutwardly so as to render impossible an insertion of the charging body16 on the grown out models. It is to be understood that this situationcan be remedied, if the models comprise a reduced total outer diameter.

[0044] Following the conclusion of the wax working, the retort form 32,which can also be formed of cardboard, is inserted onto an indentation42 of the retort base 12. Thereafter, the forming mass 28 is carefullyintroduced. The forming mass hardens into a form mass and is heatresistant with respect to the temperatures which are required for thesintering of ceramic—that is, for example, up to 1100 C.

[0045] The retort cover 30, which, in any event, comprises anindentation whose configuration corresponds to that of the indentation42, is then put on so that the retort system 10 can be manuallymanipulated as desired.

[0046] In connection with the preparation of the press, the retortsystem 10 is then preferably disposed in the position shown in FIG. 2and the retort base 12, together with the retort cylinder 14 as well asthe retort cover 30 and, additionally, the retort form 32, is removed.The forming mass 28 is thereafter somewhat pre-heated so that thecharging body 16, the support arms 20 and 22, and, as well, the waxmodels 24 and 26, melt and exit downwardly. In this condition, thepresence of some wax remnants remaining as a fluid film on the walls ofthe form does not cause any disruption or disturbance.

[0047] The forming mass 28 is then again rotated so that it is in theposition shown in FIG. 1. In this position, a ceramic blank isintroduced which has an outer diameter corresponding to that of thecharging body 16. The ceramic blank can have a height/width relation ofapproximately one to one so that it encloses a significant volume and issuitable for the filling up of large hollow spaces which correspond tothat of the wax models 24 and 26 and the support arms 20 and 22. Theceramic blank is, together with the forming mass 28, further heated,whereby the remaining wax remnants are vaporized.

[0048] It is important that the wax be handled so as to be residue-free.In this connection, the method of the invention is described, forexample, with respect to wax deployed as the material for the chargingbody 16. It is to be understood, that in lieu of this, other suitabledifferent materials can be deployed which are residue-free—that is,primarily organic materials.

[0049] In the embodiment shown in FIG. 2, the charging body 16 isconfigured as a cylindrical tube which extends over the entire length ofthe retort cylinder 14—that is, the charging body extends up to thegrowth surface 18.

[0050] It is to be understood that, in lieu of this, other embodimentsare possible.

[0051] Thus, in the embodiment shown in FIG. 3, a somewhat enlargedcharging body 16 is provided which extends outwardly of the retortcylinder 14 and covers the retort cylinder 14 on its topside (or on itsunderside in the position shown in FIG. 1). The wall thickness of thecharging body 16 on its back surface and on its cylindrical wall aredimensioned the same in this embodiment.

[0052] In order that access to the blind hole receptacle 34 is possible,in this configuration, a through receptacle 44 is provided which isaligned with the blind hole receptacle 34 and is securable in thesupport arms 20 and 22.

[0053] A modified embodiment with a multiple component charging body 16can be seen in FIG. 4. In this configuration, there is provided a spacerbody 46—in the example, a spacer ring 46—which is disposed on the retortbase 12 and is releasably inserted on the retort cylinder 14. The spacerbody 46 can, together with the retort cylinder 14 and the retort base12, be removed so that it is not lost if a pre-heating process is to beundertaken.

[0054] In this embodiment, in lieu of the pot-shaped charging body 16 asshown in FIG. 3, a ring-shaped charging body 16 can be provided as well.The charging body 16 extends outwardly over the growth surface 18,whereby the ring space between the through receptacle 44 and thecharging body 16 is filled via a charging disk 48 which, incorrespondence with the required profile, can be configured as a lost ornot lost (vaporizable or non-vaporizable) disk.

[0055] It is to be understood that, in lieu of the ring-shaped chargingbody illustrated herein, other suitable desired forms can be deployedfor the charging body.

[0056] FIGS. 5-8 show different embodiments with the same innerconfiguration having, however, differing outer forms.

[0057]FIG. 5 shows an annular-shaped outer form, FIG. 6 shows aneight-sided outer form, FIG. 7 shows a form comprised of a sphericallyrounded rhombus, and FIG. 8 shows a right angled-shape with rounded-offcorners. Suitable desired forms of the blank can be used, whereby it canbe advantageous to permit the blank outer form to deviate from thecharging body outer form in order to make possible a reduced contactsurface.

[0058]FIG. 9 shows the configuration of the forming mass 28 which servesas the press form, as soon as the retort base and the retort cylinderare removed and the mass formed of wax has melted. Channels 48 areprovided to extend outwardly in lieu of the support arms, and thelocations at which the wax models 24 and 26 are configured are providedas hollow spaces 50. The area of the charging body 16 is open so thatthe ceramic blank can be inserted therein.

[0059] It is possible that the charging body 16 as well as the spacerring 46 and the charging disk 48 can be provided with correspondingcoding such as, for example, color coding and/or corresponding text. Inthis connection, each size can be characterized by a respective colorcoding so that different sizes can be easily recognized.

[0060] The present invention is, of course, in no way restricted to thespecific disclosure of the specification and drawings, but alsoencompasses any modifications within the scope of the appended claims.

What is claimed is:
 1. A method for producing dental restorationcomponents, comprising: filling a retort cylinder 14 of a retort systemwith a forming mass 28, the retort cylinder being at least partiallyencircled by a charging body 16; hardening the forming mass 28; afterthe hardening of the forming mass, removing the retort cylinder 14 andthe charging body 16 from the forming mass, thereby leaving behind aretort; and with the assistance of a press blank apparatus, pressing apress blank having an outer contour substantially corresponding to theouter contour of the charging body 16 into the retort.
 2. A methodaccording to claim 1, wherein the step of pressing a press blank intothe retort includes pressing the press blank into the retort with apress blank apparatus having a piston whose outer contour substantiallycorresponds to the outer contour of the charging body
 16. 3. A retortsystem for a meltable model component comprising: a generally annularlyshaped retort base 12 operable to support a model formed of a massselected to melt at a melting temperature during a retort preparationprocess; a retort cylinder 14; and a charging body 16 at least partiallyencircling the retort cylinder 14, the charging body being formed of amass selected to melt during the retort preparation process.
 4. A retortsystem according to claim 3, wherein the charging body 16 is operable toreceive a ceramic mass including, in particular, a press blank, and thecharging body is at least one of a removable body and a meltablecharging body.
 5. A retort system according to claim 3, wherein at leasta portion of the charging body 16 is in the form of a tube.
 6. A retortsystem according to claim 3, wherein the charging body 16 is insertablearound the retort cylinder
 14. 7. A retort system according to claim 3,wherein the charging body 16 has a length substantially corresponding tothe length of the retort cylinder
 14. 8. A retort system according toclaim 3, and further comprising a ring-shaped spacer body 46 disposedbetween the charging body 16 and the retort base 12, wherein the spacerbody 46, the retort base 12, and the retort cylinder 14 are removablefrom the hardened forming mass.
 9. A retort system according to claim 3,and further comprising a spacer body 46 disposed between the chargingbody 16 and the retort base 12, the spacer body being meltable at amelting condition corresponding to that of the melting condition of thecharging body
 16. 10. A retort system according to claim 9, wherein thespacer body 46 has an outer contour substantially corresponding to thatof the charging body
 16. 11. A retort system according to claim 9 andfurther comprising a charging disk 48 corresponding to the inner contourof the charging body 16 mounted on an end face of the retort cylinder 14and having a wall thickness corresponding to that of the spacer body 46.12. A retort system according to claim 3 and further comprising a spacercomponent for maintaining the space between the charging body 16 and theretort base 12, and a coding indicia associated with the spacercomponent indicating via, in particular, color indicia, informationconcerning an aspect of the spacer component differentiating the spacercomponent from other spacer components including at least one of thepredetermined length and the predetermined outer diameter of the spacercomponent.
 13. A retort system according to claim 3, wherein thecharging body 16 has a relatively large axial dimension relative to itsother dimensions and includes a floor extending in at least partialcoverage over an end face of the retort cylinder
 14. 14. A retort systemaccording to claim 3 and further comprising a growth surface 18 formedon the side of the retort cylinder 14 opposite the floor thereof, andsupport arms 20, 22, mounted to the grown surface 18, for wax models 24,26 thereon.
 15. A retort system according to claim 3 and furthercomprising at least one of a blind hole receptacle 34 formed on an endface of the retort cylinder 14 and a through receptacle 44 formed on aselected one of a charging disk and the charging body
 16. 16. A retortsystem according to claim 3, wherein the charging body 16 includes acoding indicia indicating via, in particular, color indicia, that thecharging body has one of the respective wall thicknesses of a range ofparticular charging bodies suitable for use with the same respectiveretort cylinder
 14. 17. A retort system according to claim 3, whereinthe charging body 16 is annularly shaped.
 18. A retort system accordingto claim 3, wherein the charging body 16 has a non-annular outercontour.
 19. A retort system according to claim 3, wherein the chargingbody 16 is configured as a pre-finished wax piece whose melting pointsubstantially corresponds to the melting point of the wax model 24, 26.20. A press blank for a retort process comprising: a body portion; and anon-annular outer contour formed on the body portion.